The present invention relates to a semiconductor device. More particularly, the present invention relates to a technique effectively applicable to a semiconductor device having a passive component and semiconductor chips integrated as one package.
As a CPU (Central Processing Unit) used in, for example, a personal computer, a server, a game machine, etc., becomes highly efficient, a power supply circuit for driving the CPU has been required to have a high-speed response, large-current capability, as well as higher integration.
A DC-DC converter, which is used as a power supply circuit, has a structure in which a power MOSFET for a high side and a power MOSFET for a low side are coupled in series, and is controlled by a driver circuit (driver IC).
In order to realize a higher-speed and more efficient DC-DC converter, there is a semiconductor device in which there are mounted on a lead frame a semiconductor chip in which a power MOSFET for a high side is formed, a semiconductor chip in which a power MOSFET on a low side is formed, and a semiconductor chip in which a driver circuit is formed, and are integrated as one package (see, for example, Japanese Patent Laid-open No. 2005-294464).
Also, a passive component such as a capacity element is required for the purpose of stabilizing the power voltage supplied to the DC-DC converter. Conventionally, this passive component is arranged, for example, outside the package disclosed in Japanese Patent Laid-open No. 2005-294464.
The present inventors have studied to achieve a highly efficient semiconductor device by providing a passive component in a package in which a power MOSFET and a driver circuit are mounted on a lead frame, and found out a problem when mounting the passive component on the lead frame.
Further, techniques for mounting a passive component on a lead frame are disclosed, for example, in Japanese Patent Laid-open No. 2004-296624, Japanese Patent Laid-open No. 2004-356494, and Japanese Patent Laid-open No. 2002-124616. Also, a technique for mounting a semiconductor chip and a passive component in the same package is disclosed, for example, in Japanese Patent Laid-open No. 2003-243595.